With regards to GDPR, the terms ‘Data Controller’ and ‘Data Processor’ refer to the entities that are directly responsible for how and where your data is stored and processed.
Data Controller: The natural/legal person, public authority, agency or other body that collects, stores and processes your data for various purposes.
Data Processor: The natural/legal person, public authority, agency or other body that processes your personal data on behalf of the controller.
Zoho Books will be both, the controller and processor of your data. However, from your customer’s perspective, you will be the Data Controller and Zoho Books will be the Data Processor.
and GST filing.